Vesicular Rashes

A vesicle is <5 mm and a bulla is >5 mm in diameter (epidermal is flaccid; sub-epidermal is tense), a pustule is a pus-filled vesicle or bulla. The most common causes are benign lesions of the newborn (e.g., miliaria, erythema toxicum), infections, and hypersensitivity reactions. Bullous diseases resemble burns and can become emergencies.

Differential Diagnosis

• Infection
  –HSV: Primary infection followed by latent infection in sensory ganglia; recurrences triggered by cold, UV light, stress, fever; HSV-2 (genital herpes) in child suspect sexual abuse; transmission by direct contact
  –Varicella (chickenpox) and herpes zoster (VZV): Shingles, reactivation of latent virus in sensory ganglia
  –Coxsackie virus (CV): Herpangina, “handfoot-and-mouth disease”
  –Tinea (“ringworm”): Fungal infection
  –Bullous impetigo (BI): Staph, strep
  –Scabies (mites)
  –Staphylococcal scalded skin syndrome (SSSS): Tender skin, generalized exfoliation

• Contact dermatitis (CD): Poison ivy, drugs, foods, jewelry, chemicals
• Erythema multiforme (EM)/Stevens-Johnson syndrome (SJS):
  –EM: “Bull's eye rash,” central vesicle, bulla or urticaria
  –SJS: More severe, two or more mucous membranes involved
  –Triggers: Drugs (sulfonamides, NSAIDs, phenytoin), infection (herpes, EM; mycoplasma, SJS), chemicals, malignancies
• Toxic epidermal necrolysis (TEN, a.k.a. Lyell syndrome): Sudden-onset erythema, bullae, tender skin; same triggers as EM/SJS
• Neonatal
  –Erythema toxicum: In up to 60% of newborns, disappears after 1 week
  –Miliaria: Obstructed sweat ducts
  –Pustular melanosis: Pustule then macule
  –Neonatal acne
  –Sucking blisters (bullae on hand)
  –Acropustulosis
  –Eosinophilic pustular folliculitis
  –Congenital candidiasis
• Folliculitis: Staph and strep infections
• Autoimmune: Dermatitis herpetiformis (DH), pemphigus vulgaris (PV), linear IgA disease, bullous pemphigoid (BP)
• Hereditary: Incontinentia pigmenti, epidermolysis bullosa (EB)
• Others: Mastocytosis, friction, burns

Workup and Diagnosis

• History and physical exam
  –Location, exposure, associated symptoms, social history
• HSV: Tingling/burning, vesicle on red base, 7–10 days, no scar
  –HSV-1: Mouth (ulcers, vesicles), skin, cerebral (80% asymptomatic); “herpetic whitlow” (fingers); “herpetic gladiatorum” (contact sports)
  –HSV-2: Genital, congenital; encephalitis (temporal lobe), dissemination, superinfection, keratitis

• Varicella: Red pruritic macule/papule on face, trunk; then vesicle/pustule on red macule; then noncontagious crust/scab; can get superinfection, pneumonia, encephalitis, hemorrhagic varicella
• H. zoster: Face/trunk, single dermatome, coalescing and grouped vesicles, crust after 7 days, common in immunocompromised patients, rare in children
• CV: Red macule/papule/vesicle on posterior oropharynx, hands, feet; may result in myocarditis
• Tinea: Can have kerion, a fluctuant mass with pustules
• BI: Erosion, honey-colored crust with adjacent bulla
• SSSS: Nikolsky sign, skin rubbing leads to bulla/peeling
• EB: Trauma, warm weather results in bulla

• Labs/Studies
  –HSV/VZV: PCR, culture of lesions/fluids; Tzanck test: scrape from vesicle base shows multinucleated giant cells/nuclear inclusions; brain MRI/EEG (HSV)
  –Tinea: KOH preparation, culture, or Wood lamp
  –DH: Test for celiac disease (tissue transglutaminase)
  –Biopsy when diagnosis unclear

Treatment

• HSV/VZV: Topical or systemic antivirals (e.g., acyclovir), topical anesthetics
• BI: Antibiotic for staph, strep
• EM/SJS/TEN: Symptomatic (TEN is similar to burn; use fluid therapy, emollient, antihistamine, topical anesthetic, Burow solution compresses), remove/treat cause, treat superinfection
• Tinea: Topical or oral (t. capitis) antifungal
• Scabies: Permethrin cream
• SSSS: Treat as TEN plus systemic antibiotic
• CD: Topical/systemic corticosteroid, antihistamine
• Folliculitis: Mild, topical; severe, systemic antibiotic
• DH/linear IgA disease: Oral sulfapyridine or dapsone
• PV/BP: Systemic corticosteroid, immunosuppressant
• Prevention: Varicella vaccine, VZIG (immunoglobulin) to prevent varicella after exposure; avoid exposure to causative agents

Book Source Details

• Book Title: In A Page: Pediatric Signs and Symptoms
• Author(s): Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan
• Year of Publication: 2007
• Copyright Details: In A Page: Pediatric Signs and Symptoms, Copyright © 2007 Lippincott Williams & Wilkins.

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Copyright Details: In A Page: Pediatric Signs and Symptoms, Copyright © 2008 Williams & Wilkins.

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• Back to symptom: Rash: Introduction (review 1085 causes)
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More About This Book: Title: In A Page: Pediatric Signs and Symptoms Authors: Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan Publisher: Lippincott Williams & Wilkins Copyright: 2007 ISBN: 1-4051-0427-9